Multiple mode geneva drive mechanism

ABSTRACT

A geneva drive mechanism having output feed wheels which rotate about a common axis, for driving a document selectively in either an incrementing mode or a continuous transport mode.

United States Patent Inventors Jess J. Schweihs Rochester, Minn.; Klaus Hausler, Columbia, Mo. App]. No. 837,829 Filed June 30, 1969 Patented Oct. 12, 197 1 Assignee International Business Machines Corporation Armonk, N.Y.

MULTIPLE MODE GENEVA DRIVE MECHANISM 8 Claims, 3 Drawing Figs.

US. Cl 271/51 Int. Cl B65h 5/06 [50] Field of Search 27l/51,52, 53

[56] References Cited UNITED STATES PATENTS 3,002,677 10/1961 I-Ianey et a1 271/51 X 3,027,068 3/1962 Rinzoiwai et al. 271/51 X 3,494,612 2/1970 Killam 271/51 Primary Examiner.loseph Wegbreit Attorneys-Hanifin and .lancin and Robert W. Lahtinen ABSTRACT: A geneva drive mechanism having output feed wheels which rotate about a common axis, for driving a document selectively in either an incrementing mode or a continuous transport mode.

MULTIPLE MODE GENEVA DRIVE MECHANISM BACKGROUND OF THE INVENTION .mentpast an operating station or movement of the document past the operating station at the transport speed of the device when an operation is not to be performed or an operation has been completed before total passage of the document past the operating station in the incremental mode of transport. Thus when the document such as a card has data entered thereon over only a portion of the length of the card, the effective operating speed and overall information throughput of a reading device can be increased by ejection of the document from the read station at the elevated transport speed when the reading of data is complete. To accomplish this it is usually necessary to providefor a portion of the transport structure at each longitudinal side of the incrementing drive to assure control during all document positions along the card path adjacent to the operating station. It is further usually necessary to sequence the operation of these two mechanisms to assure continuous uniform drive of the two documents.

SUMMARY In the dual mode incrementing and transport drive structure of the present invention a single input drives both incrementing and continuously rotating feed rolls about a single axis transverse to the document guideway, by selectively actuating respective pressure rolls to cause document control by the desired feed roll. The transport functions in either the step wise incrementing mode or the elevated speed transport mode. It is'also possible to effect a transfer between incrementing drive and continuous transport during the condition of identical or near identical velocity to minimize or eliminate the possibility of damage either to the document or data entered thereon which might occur if acceleration accompanies the transfer of document control.

Brief Description of the Drawings FIG. 1 is an elevation of the document drive mechanism of this invention taken parallel to the axis of the output feed wheels, partly in section and partly broken away. FIG. 2 is an elevation of the drive mechanism of FIG. 1 taken perpendicular to the axis of the feed wheels. FIG. 3 is a partial section taken along line 3--3 of FIG. 1 with elements shown in phantom view.

Detailed Description Referring to P16. 1 the geneva mechanism is mounted in the housing 11 which is secured to the associated machine in fixed relation with respect to the bed plate 12. The upper surface 14 of bed plate 12 and the surface 15 of the flange 16 form a document guideway.

The input shaft 20 is received in bearings 21 and 22 mounted in housing wall apertures and carries a spur gear 24 and the geneva drive pinion 25 for rotation in unison therewith. As also shown in FIG. 3, the geneva drive pinion includes a pin 26 and a projecting circular lock up surface portion 27. An output shaft 29 is mounted in housing 11 in bearings 30 and 31 and has rigidly connected thereto, geneva gear 33 and an incrementing feed wheel 35 which has a peripheral surfacing of high friction material. The geneva gear 33 has six equiangularly spaced radial slots 36 extending radially inward from the periphery with concave circular lock up surfaces 37 intermediate each of the slots.

An eject feed wheel assembly is joumaled about the output shaft 29 to permit rotation of gear 39 and wheel 38 about the axis of the output shaft independent of the rotational motion of such shaft. The eject feed wheel 38 has the same diameter as the incrementing feed wheel 35 and is similarly surfaced along the periphery with a high friction material. The eject feed wheel assembly in addition to wheel 38 includes a spur gear portion 39 having the same pitch pitch diameter as the spur gear 24 by which it is drive. Accordingly the rotational speed of the eject wheel assembly is identical to that of the input drive shaft 20.

Overlying the document guideway are pressure rolls 41 and 42 which are respectively aligned with. feed rolls 35 and 38.

Frame 44 has depending legs 45 and 46 which respectively form the cores for electromagnet coils 47 and 48. Pressure roll 42 is mounted on lever 50 which pivots about pin 51 and is biased by spring 52 (FIG. 1) to nonnally urge pressure roll 42 away from drive roll 38. The transversely extending lever portion 54 serves as an armature which upon actuation of coil 48 is attracted upward toward the pole face 55 against the biasing force of spring 52 to pivot pressure roll 42 toward feed wheel 38 causing a document 56 therebetween to be advanced in unison with a tangential motion of such feed wheel 38. ln like manner pressure roll 41 carried by lever.57 is normally biased by spring 58 in an upward direction away from feed wheel 35 and upon coil 47 becoming energized the armature portion 59 of lever 57 is upwardly attracted to the magnet pole causing pressure roll 41 to be urged toward feed roll 35 whereupon a document confined therebetween is induced to moving units with the tangential motion of feed wheel 35. Coils 47 and 48 are alternately actuable to respectively place a document under control of the continuously running feed wheel 35 or under control of the incrementing feed wheel 38.

The device illustrated includes feed wheels 35 and 38 which are of the same diameter with feed wheel 38 driven through gears 24 and 39 which have the same pitch diameter, being operated at the same rotational speed as input shaft 20. The six slot geneva gear 33 has the same rotational velocity at the midpoint of the incrementing portion of the cycle as input shaft 20. Consequently, at such midpoint of the incremental motion of the feed wheels 35 and 38 have the same velocity. By timing the transfer of document motion control between feed wheel 35 and feed wheel 38 to coincide with the occurrence of common velocity, instantaneous document acceleration at the time of transition is avoided and thereby such document damage or impairment of the data carried by document are minimized or eliminated.

in operation, shaft 20, spur gear 24 and geneva drive pinion 25 which are interconnected for unitary rotational motion are rotated continuously. The eject feed wheel assembly including wheel 38 and gear 39 are likewise continuously rotating as gear 39 is driven by gear 24. Geneva gear 33 is driven from shaft 20, being alternately driven by pin 26 during that portion of the shaft rotation during which such pin is received in one of the slots 36 and restrained against rotation during the period of shaft rotation when lock up surface portion 27 engages the cooperating gear lock up surface 37. Accordingly, during each revolution of shaft 20 and geneva drive pinion 25 which is secured thereto, geneva gear 33 experiences a period of motion during which it is accelerated and decelerated to effect one-sixth of a revolution and period of dwell during which it is stationary. Since gear 33 and feed wheel 35 are both secured to shaft 29 for rotation in unison therewith, feed wheel 35 is also continuously incremented experiencing a period of rotation in the same direction as feed wheel 38 and a period of dwell during each revolution of shaft 20.

. When coil 47 is energized, pressure roll 4k is urged toward incrementing feed wheel 35 causing a document retained therebetween to have a linear incremental motion imparted thereto. in like manner, energizing coil 48 causes pressure roll 42 to be urged toward continuously running feedwheel 38 to impart to a document 56 compressed therebetween the tangential velocity of feed wheel 38.

Since it is necessary that a document 56 be subject to driving engagement with only one of the feed wheels 35 and 38 at any give time, the actuation of coils 47 and 48 are controlled to be energized in the alternative and precluded from simultaneous energization. This may be accomplished for example by controlling actuation of the coils respectively by the set and reset outputs of a conventional electronic latch or flip-flop. As control is selectively changed from one to the other of coils 47 and 48 the biasing force of the respective spring 58 or 52 causes the pressure roll associated with the deactivated coil to be pivoted away from the operative position to the separated, inoperative position illustrated by the position of lever 50 in FIG. 2.

As pin 26 of geneva drive pinion 25 engaging one of the slots 36 of geneva gear 33 is at the midpoint of the cycle of incremental motion, shown in FIG. 3, the effective pitch circles are equal. At that point the rotational velocity of geneva gear 33 is identical to the rotational velocity of shaft 20. Accordingly, the instantaneous rotational velocity of feed wheel 35 is equivalent to that of shaft 20 and feed wheel 38 and timing the transfer of document control from one feed wheel to the other to occur at such time in the increment cycle does so without subjecting the document to an instantaneous acceleration.

What is claimed is:

l. A geneva type document drive mechanism having dual drive modes comprising:

an input shaft;

an output shaft;

first and second feed wheels which rotate independent of one another about the axis of said output shaft;

geneva drive means interconnecting said input shaft to said first feed wheel for converting continuous rotation of said input shaft to step wise incremental motion of said output shaft; and

connecting means for transmitting continuous rotating motion of said input shaft to said second feed wheel.

2. The drive mechanism of claim 1 wherein said geneva means includes a geneva drive pinion secured to said input shaft for rotation in unison therewith and cooperates with a geneva gear wheel, and said first feed wheel, output shaft, and geneva gear wheel are secured together as a unitary structure for rotation about a common axis.

3. The drive mechanism of claim 2 wherein said second feed wheel is joumaled about said output shaft and rotates with a tangential speed equivalent to the document transport speed of the associated device.

4. The drive mechanism of claim 3 wherein said geneva gear includes six uniformly angularly spaced radially inwardly extending slots with arcuate lock up surface portions peripherally intermediate each of said slots.

5. The drive mechanism of claim 4 wherein said second feed wheel is driven at the same rotational speed as the input shaft.

6. The document drive mechanism of claim 2 further comprising means defining a document guideway with the peripheral surfaces of said feed wheels closely adjacent said guideway, and selectively operable means actuable to effect control of movement of a document along said guideway by one of said feed wheels.

7. The document drive mechanism of claim 6 wherein said selectively operable means comprises first and second alternately operable electromagnetically actuated pressure rolls disposed at the opposite side of said guideway and respectively aligned with said first and second feed wheels for confining a document, whereby upon actuation of one of said pressure rolls a document confined between such pressure roll and the associated feed roll is advanced in accordance with the tangential motion of such associated feed roll.

8. The drive mechanism of claim 3 wherein said first feed wheel accelerates during incremental motion to a rotational velocity at least as great as the rotational velocity of said second feed wheel. 

1. A geneva type document drive mechanism having dual drive modes comprising: an input shaft; an output shaft; first and second feed wheels which rotate independent of one another about the axis of said output shaft; geneva drive means interconnecting said input shaft to said first feed wheel for converting continuous rotation of said input shaft to step wise incremental motion of said output shaft; and connecting means for transmitting continuous rotating motion of said input shaft to said second feed wheel.
 2. The drive mechanism of claim 1 wherein said geneva means includes a geneva drive pinion secured to said input shaft for rotation in unison therewith and cooperates with a geneva gear wheel, and said first feed wheel, output shaft, and geneva gear wheel are secured together as a unitary structure for rotation about a common axis.
 3. The drive mechanism of claim 2 wherein said second feed wheel is journaled about said output shaft and rotates with a tangential speed equivalent to the document transport speed of the associated device.
 4. The drive mechanism of claim 3 wherein said geneva gear includes six uniformly angularly spaced radially inwardly extending slots with arcuate lock up surface portions peripherally intermediate each of said slots.
 5. The drive mechanism of claim 4 wherein said second feed wheel is driven at the same rotational speed as the input shaft.
 6. The document drive mechanism of claim 2 further comprising means defining a document guideway with the peripheral surfaces of said feed wheels closely adjacent said guideway, and selectively operable means actuable to effect control of movement of a document along said guideway by one of said feed wheels.
 7. The document drive mechanism of claim 6 wherein said selectively operable means comprises first and second alternately operable electromagnetically actuated pressure rolls disposed at the opposite side of said guideway and respectively aligned with said first and second feed wheels for confining a document, whereby upon actuation of one of said pressure rolls a document confined between such pressure roll and the associated feed roll is advanced in accordance with the tangenTial motion of such associated feed roll.
 8. The drive mechanism of claim 3 wherein said first feed wheel accelerates during incremental motion to a rotational velocity at least as great as the rotational velocity of said second feed wheel. 